Study On The Performance Of Nearshore Ship Self-propulsion And Fluid-structure Interaction Of Aft Propeller

Under the influence of scale efficiency,the main scale of ships is getting larger and larger,which leads to the derivation of natural rivers,artificial canals,harbors and other waterways into restricted waterways,and the speed and maneuverability of ship navigation are greatly challenged due to the block effect in restricted waterways,so the speed and maneuverability of ships navigating in restricted waterways has been a hot issue of concern for research scholars.Compared with open water,the flow field around the ship in restricted channel is more complex and changeable,the propeller behind the ship works in this complex non-uniform flow field,the hydrodynamic characteristics will be changed,at the same time the action of the water will lead to the deformation of the propeller,and the propeller deformation further affects its own hydrodynamic characteristics,this behavior can be called the hydro-elastic behavior of the propeller.Obviously,the hydroelastic behavior of the propeller behind the ship is more complex than the hydro-elastic behavior of the propeller in open water,therefore,it is necessary to link the ship hull with the propeller for research.In this thesis,the self-propulsion performance of a ship navigating in restricted waters and the fluid and structure interaction of the propeller behind ship are investigated.The modern container ship KCS and its supporting propeller KP505 are taken as the object of study,and based on RANS method and overset grid technology,the commercial software STAR-CCM+ is used to conduct numerical simulation of ship self-propulsion test in restricted waterways.On the basis of obtaining the information of the stern companion flow field in restricted waterways,the fluid and structure interaction module in STAR-CCM+ is used to carry out the numerical simulation of the propeller fluid and structure interaction in non-uniform flow field.Firstly,numerical simulations of ship-rudder system towing test in restricted waterways are carried out with different water depths,ship-wall distance and speed as parameters to analyze the effects of shallow water effect and wall effect on the hydrodynamic characteristics and flow field characteristics of the ship.Then,the scale effect between the model-scale ship and the full scale ship is considered,and the frictional resistance correction is applied to the ship model.Based on the initial flow field of towing in restricted waterways,a propeller is introduced to provide thrust,and the self-propulsion point of the full-scale ship is obtained by varying the propeller speed to realize the numerical simulation of the ship self-propulsion test in restricted waterways.In the process of analyzing the ship self-propulsion characteristics in restricted waterways,the water depth and ship-wall distance are unified and the half-ship blockage ratio is used as a parameter to study the influence of blockage ratio on the ship propulsion characteristics at different speeds.At the same time,the changes of the ship,propeller and rudder interaction and the exciting force and flow field characteristics of the propeller behind the ship under different blockage ratios are analyzed.Finally,the hydro-elastic behavior of the propeller in the non-uniform flow field is investigated with the obtained companion flow field behind the ship in the restricted water as the input field,and the hydrodynamic characteristics and structural response of the propeller in the uniform flow field are compared.In this thesis,some basic laws of the self-propelled performance of the ship in restricted waterways and the coupling characteristics of the aft propeller fluid-structure in restricted waterways are studied by means of numerical simulations,which provide a reference for better understanding and analysis of the ship-propeller-rudder system coordination and the propeller hydro-elastic behavior in restricted waterways.